How-to: Freelensing

The era of digital sensors has created a pervading fear of dust among photographers. Many shooters try not to change lenses except when they have to, and they pale at the thought of a gaping-open lens mount. But sometimes it's worth throwing caution to the wind. Often times I find the wrong way to use my equipment is the best way. Let me introduce you to the world of freelensing.

What's striking about the image below?

OK, more than anything else, it's Claudia herself. But the real trick is that the plane of focus isn't what we expect. Generally, lens-makers work very hard to make sure that their glass produces a flat plane of focus -- meaning no matter how shallow your depth of field, if her face is in focus, the rest of her is going to be more or less in focus as well. But here it's WAY out, and a sparkly dress shows a dramatic bokeh effect. What's going on? The focus plane is tilted. At the top of the image, something about six feet away would be in focus—and at the bottom, something about six INCHES away would be in focus, and that same six-foot-away object is not.

There are numerous ways to achieve similar effects in photography from tilt-shift lenses to Lensbabies, which rely on the simple optical trick of bending your lens at tilted angles relative to your sensor. Or you can do it with lenses you have lying around, by freelensing, a technique where you take photos with your lens not firmly mounted on your camera body. "Woah woah woah!" you might say. "Isn't that risky? Couldn't you get dust in your sensor or drop your lens?" Well, yes. Don't try freelensing unless you're comfortable with the idea. But unless you attempt it in a sandstorm, it's not as risky as it sounds.

Freelensing while hair-spray is flying around increases risk, but anything for the shot, right?

When freelensing, the lens is not very far from the camera. Due to optical laws (not worth extrapolating here), as you move your lens away from your camera, it effectively becomes near-sighted, losing the ability to focus at infinity but allowing you to focus closer than you normally would. And it doesn't take much - generally less than an inch. Because of this near-sighted effect, the easiest way to freelens is to manually focus your lens out to infinity, turn off your camera, detatch your lens, turn your camera back on, and then physically move the lens to get your subject in focus. Then you can tilt it up or down, left or right and watch how the focus plane changes.

Quick tips:

1. Since your camera is not communicating with your lens in any way, it's a good idea to manually set your exposure while the lens is still on the camera.

2. If your camera has live view, this is extremely helpful for focusing since it will show you exactly what the focus plane of the final image looks like, while most optical viewfinders do not.

3. While dust may or may not be a worry, light definitely will leak in, which can add flare and reduce contrast. If you don't want that, bend the lens toward the main light source, so the opening to the sensor is facing away from it.

One important caveat with freelensing is that this technique uses your camera in a way it's not meant to be used, meaning that different systems will have very different ways of pulling this off. For example, freelensing works with most Canon cameras, however, with Nikon cameras your life will be much easier if you use a lens with an aperture ring since modern G-style lenses close their aperture down when they are off the camera. All of these photos were taken with the Nikon 50mm f/1.2 AIS or the 85mm f/1.4D, which both have aperture rings.

For more information, including questions about how it can work with your camera and lenses, see the Freelensing group on Flickr. Is this technique for everyone? No way. Can it do everything a tilt-shift lens can? No, tilt-shift lenses are complicated mechanisms with a lot of different functions. But this way is free, and it can do some things a tilt-shift can't do as well … after all, have you ever seen an f/1.2 tilt-shift lens?

15 Comments

neil morris

1 year ago

brilliant, i have seen a post where the tog took all the mounting rings off the back of the lens to allow the rear element to sit in the aperture nearer the sensor......i have just bought a lensbaby 35 myself so am exploring, au revoir